Fergy-to 20

Take the rear wheels off and set jack stands under the axle tubes. Remove two large screws from the face of the brake drum. Loosen the brake adjuster and slide the drum off. Disconnect the linkage from the bottom of the steering brake. On the axle tube flange, right behind the backing plate, there are some nuts, six I think, remove them and the axle and backing plate and steering brake should all slide out.
The oil seal on a TO-20 is on the outside of the hub next to the axle flange. To replace it you have to remove the bearing retainer ring and then press the hub and bearings off the axle. If you decide to do this the book says to drill a 1/4 inch hole in the retainer ring and then split it with a chisel. Then press the rest apart. The other option is a product called a "sure seal". This slides over the axle and presses into the back side of the hub. It's an add on aftermarket item. I have no personal experience with them. Some say the work other say they don't. I hope this helps.
Two other things. People say that if you raise the rear you don't have to drain the fluid. Mine was drained already so I can't say. Also the manual says that if you are going to pull an axle, be sure both sides are up on jack stands. Something about a side load possibly causing damage.

Neal